Field of the Invention
The present invention relates to a metal mask and a manufacturing method thereof for depositing an organic layer on a substrate.
Description of the Related Art
A display device is a device displaying an image, and recently, an organic light emitting diode (OLED) display has received attention. Unlike the liquid crystal display device, since the organic light emitting diode (OLED) display has a self-emitting characteristic and does not require an additional light source, it is possible to reduce thickness and weight thereof. In addition, the organic light emitting diode (OLED) display has high-quality characteristics such as low power consumption, high luminance, and fast response speed.
In general, the organic light emitting diode (OLED) display includes a first electrode, a second electrode, and an organic emission layer disposed between the first and second electrodes. Generally, when the organic emission layer is deposited on the first electrode of the substrate, the organic emission layer is formed on the first electrode through pattern openings in the metal mask.
The metal mask has been manufactured by wet etching or with a laser to form the pattern openings in a blank or subject under processing (SU). However, when the pattern openings are formed by wet etching in the subject under processing, an organic material passing through the pattern openings during deposition cannot have a wide deposition angle as a lateral side of the pattern opening is formed in a specific shape according to an etching rate intrinsic to the wet etching.
Particularly, in case where the display area of the organic light emitting diode (OLED) display is increased, a deposition abnormality occurs due to the problem described above, for the organic emission layer that is formed at edge portions of the substrate. Moreover, when the pattern openings are formed in the blank by a laser, there has been a problem that the total manufacturing time is increased due to the fact that the plurality of pattern openings are respectively formed in sequence, and that each opening is produced by the laser one at a time.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention, and therefore it may contain information that does not constitute prior art as per 35 U.S.C. §102, taken either prior to or after the America Invents Act.